Born on 25 October 1834 into the Mancunian middle class, David Jones
spent part of his apprenticeship under Ramsbottom.
At the age of twenty-one he joined what would soon become the Highland Railway,
where he worked under Stroudley and with
Dugald Drummond. In 1870 he became locomotive
superintendent and, like most such occupants of that position, spent much
of his time rebuilding old engines in order to extract a few more years from
them. He was responsible for the Jones Goods 4-6-0 of the HR, the first 4-6-0
in Britain (1894). His other new designs tended to break away from the
Allan tradition which had lasted so long in Scotland,
although he continued to use the Allan link valve gear. His Loch class
4-4-0 had a very high power/weight ratio and was among the several classes
carrying his special louvred chimney. This invention involved the division
of the chimney into a central exhaust tube and an outer concentric ring into
which air was projected through the louvre slits down the front of the chimney
casing. By this means, allegedly, a draught was supplied when the engine
was running with its steam cut off, as happened for long stretches on the
hilly Highland line. Jones retired in 1896, after a scalding (experienced
during tests of the large goods 4-6-0) had robbed him of the use of his left
leg, and died in London on 2 December 1906, after a motor car accident had
deprived him of the use of his other. Jones had a son,
Hugh who was apprenticed at Lochgorm
and left to work on the Sourh African Railways..

Atkins makes the following
observations about the 4-6-0:Over the years there has been
some debate as to the precise origins of the design of this, the first British
4-6-0, and as to its supposed derivation from a certain prolific Indian
locomotive class. Suffice it to say that the credit for its adoption and
success should fall squarely on the shoulders of David Jones, the HR Locomotive
Superintendent. It says much for his original concept that, disregarding
inevitable and purely superficial modifications, the engines remained basically
unaltered throughout their long and useful lives. These extended well into
a regime pursuing a policy of ruthless locomotive standardisation, which
brought about the early demise of many more recent and more numerous examples
of the same wheel arrangement from other lines.

The Highland had thus, for the moment, obviated the 0-6-0 employed
by practically every other British railway except the HR's neighbour and
bitter enemy, the Great North of Scotland. A 0-6-0, however, would have meant
a crank axle, and crank axles did not have a place in Jones' book. Jones
was a fervent disciple of Alexander Allan, but one Allan feature Jones did
not perpetuate in his 4-6-0s was double framing around the outside cylinders.
Allan's straight link valve gear was retained; this was basically similar
to the corresponding Stephenson gear, but the link was easier and therefore
cheaper to make and imparted a constant lead irrespective of cut-off. Atkins
also makes it abundantly clear that the "Drummond" Castle class was:
mechanically... pure Jones, although their Drummond stamp of chimney, cab
and ugly 'water-cart' bogie tender was unmistakeable. A dubious asset, without
which none of the younger Drummond's locomotives was complete, was the provision
of steam reverse, a troublesome mechanism if it were not well
maintained.

As well as discussing Jones' 4-4-0 designs, notably the Loch class,
Middlemass (Scottish 4-4-0) notes
that in 1890 Jones had been offered Stroudley's former position on the LBSCR
following his death in Paris, and consders this to have been a highly interesting
"might have been"..

Louvres for chimneys

F.C. Johansen made a written contribution (507-9) which considered
Jones' louvred chimneys on the HR and the increase in air resistance induced
by deflector plates..